1. Field of the Invention
The present invention relates to a burner in which the fuel is preheated to relatively high temperatures in a heat exchanger located in a water jacketed burner combustion chamber, the burner also being characterized by intimate mixing of the preheated fuel with naturally aspirated air to produce a stoichiometric mixture whose combustion produces minimum pollutant emissions.
2. Description of the Prior Art
Conventional burners for steam generation boilers and other end applications are generally characterized by high pollutant exhaust emissions, and particularly high levels of nitrogen oxide and carbon monoxide. This is primarily because of incomplete combustion. More stringent emissions standards and thermal efficiency requirements have brought great pressure on the burner industry to either improve or phase out such outmoded burners.
Natural gas, methane and propane are typically used in such burners. Natural gas is preferred, but it is only available from most distribution systems at relatively low pressure. Prior art burners have therefore had to use fuel pumps or compressors to increase the fuel pressure necessary for steady state burning.
In addition, the combustion temperatures which characterize most prior art burners are relatively low because of the susceptibility of such burners to thermal breakdown or actual melting at the higher temperatures which produce more complete combustion and consequently lower pollutant exhaust emissions.
Also, prior art burners have been deficient in failing to provide the turbulent and thorough mixing of fuel and air necessary to achieve complete combustion.